Standardize usage of virtual/override/final specifiers.

chrome/browser/chrome_browser_main_linux.h

Index: chrome/browser/chrome_browser_main_linux.h
diff --git a/chrome/browser/chrome_browser_main_linux.h b/chrome/browser/chrome_browser_main_linux.h
index e70f2fcd72f2f1c547c016d13bcd5b7e9d8200fd..aa9ff2faa3457cde1d26d7da624c81286ff312de 100644
--- a/chrome/browser/chrome_browser_main_linux.h
+++ b/chrome/browser/chrome_browser_main_linux.h
@@ -14,12 +14,12 @@ class ChromeBrowserMainPartsLinux : public ChromeBrowserMainPartsPosix {
  public:
   explicit ChromeBrowserMainPartsLinux(
       const content::MainFunctionParams& parameters);
-  virtual ~ChromeBrowserMainPartsLinux();
+  ~ChromeBrowserMainPartsLinux() override;
 
   // ChromeBrowserMainParts overrides.
-  virtual void ToolkitInitialized() override;
-  virtual void PreProfileInit() override;
-  virtual void PostProfileInit() override;
+  void ToolkitInitialized() override;
+  void PreProfileInit() override;
+  void PostProfileInit() override;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ChromeBrowserMainPartsLinux);